1)We observed the role of fibronectin in S.aureus infection using immunohistochemistry and immunoelectron microscopy. Soluble fibronectin began to deposit in a fine granular pattern in the dermis and gradually increased with time. At 24 h two patterns of binding were seen. In one pattern, fibronectin was bound to a part of the cell surface of microorganisms. This suggests that fibronectin helped staphylococcus cells to attach to fibrin or connective tissues. The other pattern of fibronectin binding was the binding of fibronectin all around the cells. The pattern could be interpreted as inhibition by fibronectin of S.aureus attachment to the fibrins and tissues.2)We produced an experimental staphylococcal impetigo model in mice by epicutaneous inoculation with S.aureus and observed the lesions by microscopy and electronmicroscopy. Our new method produce human impetigo-like blister may contribute to disclosing the mechanisms of blister formation in epidermis by S.aureus. Electronmicrosco
… Morepically, S.aureus cells invaded the horny layer at 1/4 h and 1 h, and a clear halo was seen between S.aureus cells and horny cells. S.aureus cells attached to surrounding horny cells by fibril-like structures. These structures were not observed at later points in time. This process is thought to be a necessary first step for the establishment of the infection.3)Staphylococcal impetigo was produced in mice by epicutaneous inoculation of a strain isolated from human impetigo in the evaluation of topical or systemic antimicrobial agents in the treatment of impetigo. Although after a sufficient chemotherapy S.aureus cells in the lesions morphologically changed, viable S.aureus cells remain in the horny layer. It could suggest that microorganisms in the horny layer are not easily eradicated by antimicrobial agents.4)In the experimental sepsis model using mice, we observed that S.aureus could not attach to the normal skin but could attach easily and proliferated on the injured skin and/or irritated skin with croton oil. Less